In treating toilet flush water with chemicals in order to produce desirable effects such as bowl aesthetics, cleaning, disinfection, deodorization, aerosol reduction, etc., it is desirable that the chemicals be dispensed into the flush water automatically each time the toilet is flushed. The prior art discloses numerous devices which have been designed for this purpose.
Particularly desirable devices are those comprising a solid cake composition. In this type of device a measured amount of water enters the device during one flush cycle and remains in contact with the cake between flushes, thereby forming a concentrated solution of the composition which is dispensed into the flush water during the next flush. The advantages of such devices are that the chemical composition can be packaged and shipped in more concentrated form than aqueous solutions of the chemicals. Also, the problems of liquid spillage resulting from breakage of the dispensers during shipment or handling is eliminated.
Prior art surfactant cake compositions are disclosed in U.S. Pat. Nos. 4,308,625, Kitko, issued Jan. 5, 1982 and 4,043,931, Jeffrey et al, issued Aug. 23, 1977. These patents disclose a lavoratory cleansing tablet which is formed with two or more nonionic surfactants which includes the use of polyalkoxylated alcohols. U.S. Pat. No. 4,477,363, Wong et al, issued Oct. 16, 1984, discloses a solid cake comprising free fatty alcohol and a buffered alkali earth metal alkyl sulfate surfactant. U.S. Pat. No. 4,310,434, Choy et al, issued Jan. 12, 1982; and U.S. Pat. No. 4,278,571, Choy, issued July 14, 1981, entitled "Surfactant Cake Compositions"; all of which are incorporated herein by reference, disclose surfactant cake compositions containing dyes and perfumes which are utilized in the present invention. The surfactants provide cleaning and sudsing in the toilet bowl and also serve to dispense other components of the compositions such as dyes, perfumes, organic resins, etc.
Water-soluble inert salts such as alkali metal chlorides and sulfates are used in such compositions to act as a "filler" so that the composition can be formed into cakes of desirable size without using excessive amounts of active ingredients. The predominant ingredients of the cake compositions are usually the surfactant, perfume and the filler salt.
A major problem in this art has been short and/or erratic longevity of surfactant cakes because of rapid and uneven dissolution resulting in decreased cake stability and longevity.
It has been found that a solid cake composition which is preferably cast and has a long and uniform block life can be provided where the composition comprises the combination of a polyethylene glycol distearate having a specific water solubility and molecular weight range with the conventional materials such as fillers, binders, dyes, fragrances, extenders and the like.
It is an object of the present invention to provide a solid cake compositions which may be formed by casting and comprises a specific kind of polyethylene glycol distearate, which compositions are suitable for use for automatically dispensing cleaning agents into the toilet.
It is a further object of the present invention to provide a cast solid cake composition having relatively high melt temperatures and less block surface tackiness for improved processing.
It is a still further object of the present invention to provide a lavoratory block which has a long and uniform block life that eliminates sluggish toilets.
It is a yet still further object of the present invention to provide a lavoratory block which resists mounding and major fragmentation.
Other objects, advantages and novel features of the present invention will be apparent to those skilled in the art from the following description and appended claims.